1. Field of the Invention
This invention concerns the chemical compound N,N-dimethyl-N'-isobutyl-N'-.beta.-hydroxyethyl-propylenediamine, a process for its preparation and its use.
2. Discussion of the Prior Art
It is known that the addition of compounds with labile hydrogen to isocyanates, leading to the formation of polyurethanes, is catalyzed by tertiary amines. Certain tertiary hydroxyalkylamines have also been described as catalysts for the preparation of polyurethanes from the aforementioned starting substances. Thus, dimethylethanolamine may, for example, be used for this purpose. However, a disadvantage is the fact that this compound is rather volatile and has poor gel formation and hardening properties. Dimethylethanolamine is thus generally used only as a co-catalyst in conjunction with other catalysts.
German Offenlegungsschrift 26 25 684 describes a process for accelerating addition and polymerization reactions of organic isocyanates by base catalysts.
In this procedure, hydroxyalkyl-tert.-amines having at least one primary hydroxyethyl group of the general formula ##STR1## where Y is CH.sub.3 or Z,
Z is CH.sub.2 --CH.sub.2 --OH and PA1 n is 1 or 2,
are used as catalyst.
These compounds are, it is true, suitable as catalysts for preparing polyurethanes from isocyanates. Their preparation according to the Leuckart synthesis by reacting amines with aldehydes or ketones by heating with formic acid is, however, commercially costly and, on account of the necessary large excess of formic acid and the complicated working up of the reaction product, cannot always be carried out economically.
It is an object of this invention, therefore, to provide a readily obtainable catalyst for catalyzing the addition of compounds with labile hydrogen to isocyanate, which catalyst can moreover be produced industrially in a simple manner.